Process control systems often employ electronic regulators, such as microprocessor based PID (Proportional, Integral, Derivative) controllers, to precisely control pressures. Electronic regulators can act as standalone units to control the pressure of clean, dry, inert gases, or can be connected to any pneumatically actuated regulator or valve. For example, an electronic regulator may control a pneumatically actuated regulator, via a pilot pressure, to precisely control the pressure in a line leading to a tank or other vessel.
In an emergency situation (e.g., loss of power), or in other situations in which an electronic regulator is to be shutoff, pilot pressure can be trapped within the electronic regulator due to the common use of normally closed inlet and exhaust valves. The trapped pilot pressure may, for example, maintain an actuator at a static position, preventing the actuated valve from moving to its fail safe position (e.g., normally opened or normally closed). To release this pilot pressure, current systems utilize a vent valve disposed in an external adaptor or coupling (e.g., in an adaptor connecting the electronic regulator to a pneumatically actuated regulator). However, such an external vent valve often requires bulky and exposed wiring and introduces additional leak points into the pressure controlled system.